Improvements in sewing machines



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ATTORNEY.

Patented Mar. 31, 1936 UNITED STATES ATENT OFFICE Alfons Strobel, Munich, Germany; Minna Strobel, sole heiress of said Alfons Strobel, deceased Application September 11, 1933, Serial No. 689,020 lln Germany September 14, 1932 '7 Claims.

The invention relates to sewing machines having mechanism whereby the edges of two layers of cloth to be joined by a line of stitches are subjected to what is called edge rubbing, the said mechanism comprising two rubbing members which engage the top and bottom layers respectively and are reciprocated in opposite directions transversely of the line of feed.

An object of the invention is to provide edge rubbing mechanism which operates with adequate thoroughness but with a minimum of liability to shift the cloth from its path. According to the invention the rubbing members are rollers rotatably mounted on reciprocating carriers whereby they are held against the cloth. The invention includes also arrangements whereby the edge rubbing mechanism assists or effects the cloth feed, and it also includes means for effective lubrication of the mechanism, as will be described hereinafter.

Two embodiments of the invention are shown in the accompanying drawings, in Figs. 1 to 6 and in Figs. 7 to respectively.

Fig. 1 is a front view of the first embodiment,

and

Fig. 2 is a side view thereof, seen from the left of Fig. 1,

Fig. 3 is a section on the line A-B of Fig. 2,

Fig. 4 a section on the line C-D of Fig. 1,

Fig. 5 a rear View, partly in section on the line E-F of Fig. 4, and

Fig. 6 a plan View, partly in section on the line G-H of Fig. 5.

Fig. '7 is a front view of the second embodiment of the edge rubbing mechanism, and

Fig. 8 is a plan view thereof, partly in section on the line N-O of Fig. 7,

Fig. 9 being a section on the line J-K of Fig. 8, and

Fig. 10 a section on the line L-M of Fig. 8.

Referring first to the construction shown in Figs. 1 to 6, a driving pulley I is fixed to a shaft 2 having a ball hearing at one end and a plain bearing 30 at the other end. Fixed to the shaft 2 is a gear wheel 4 engaged with a gear wheel 5 fixed to a shaft 6 actuating the hook i (Fig. 2) and work feed mechanism 8, 9, ill, ll, i2 (Figs. 5" and 6). The shaft 6 also has thereon an eccentric l3 the strap of which is connected by a rod M to the needle arm l5 (Fig. 3).

For edge rubbing the shaft 2 has fixed upon it a bevel wheel l6 engaged with a bevel wheel I"! on a shaft [8, on which there are two eccentrics I!) set at 180 to each other. The straps of these eccentrics have brackets 2|], 2| to which are fixed bars 22 and 23 respectively, so that by rotation of the shaft la the bars are reciprocated in opposite directions, as indicated by a double-headed arrow in Fig. 6. The bars 22, 23 work in contact with a vertical guide 24, and the bar 23 has near its free end a horizontal slot 23a engaged with a roller 25 pivoted to the guide 24. The free end of the bar 22 is capable of limited upward movement against the action of a spring 26 (Fig. 1) connecting it to the bar 23.

At their free ends the bars 22, 23 have gudgeons 21, Zla, and on these gudgeons there are rotatable rollers 28, 280 having circumferential ribs or serrations. These rollers are held by the bars over and under the path of cloth, so that the two layers of cloth pass between them, with the roller 23 pressed against the top layer by the action of the spring 26. The spring allows the roller 28 to accommodate itself tothe thickness of the cloth.

The serrations of the rollers are fiat and vertical on one side, and inclined on the other side, so that in cross section they resemble ratchet teeth, as best shown in Fig. 1. They consequently obtain a grip on the cloth when moving towards the left of Fig. 1, with a tendency to move the work towards the left, and they produce an effective rubbing action, while themselves rolling on the cloth and helping to keep it to its appointed path.

The cloth issuing from between the rollers is engaged by two gripping jaws 29, 29a adjustably fixed to the bars 22 and 23 respectively, and these jaws hold the two layers of cloth tightly together on their way to the stitching mechanism.

In the modification shown in Figs. 7 to 10 the edge rubbing mechanism is capable of a horizontal rocking movement, as indicated by a doubleheaded arrow in Fig. 8. The reciprocating bars,

designated 22a, 23a, are engaged with a guide member 24a which is rotatable about a vertical pivot 41, and to allow of horizontal rocking move ment the eccentrics l9a, 19b actuating the bars are segments of spheres, with straps of corresponding shape, as shown in Fig. 8. A link 48 (Figs. 8 and 9) connects the member 240. to the cloth feed mechanism 9, So, so that the edgerubbing mechanism takes part in the horizontal feed movement.

On the shaft 6 is a cam 69 (Figs. '7, 8 and 10) coacting with a lever 50 pivoted to the machine frame at 5| and acting through a roller 52 on a U-shaped bracket 54, which has a pin and slot connection 54d with a lever 55 pivoted at 55a to the guide member 24a. The bracket 54 is supported for vertical adjustment by a set screw 53 carried by the lever 55. The lever 50 is rocked downwards by the cam 49 and this movement of the lever 50 is transmitted by the roller 52 to the member 54, and thence through the set screw 53 to the lever 55, against the action of a spring 550 (Fig. 7). The lever 55 engages with its forked end a pin 56a on a bar 56 vertically slidable in a guide 56b on the guide 24a. At 51a there is pivoted to the guide 24a a double armed lever 51, which is connected by a link 58 to the lever 55, said lever 5'! engaging with its forked end a pin 59a on a bar 59 vertically slidable in the guide 551). The bars 56, 59 are connected to levers 23a, 22a by rollers a, 6|] respectively, said rollers being carried by the bars and engaging slots in the levers 23a, 22a as shown.

The operation of this device is as follows: When the feeder plate 12 ceases to feed and drops below the needle plate, the cam 49 acting on the lever 50 causes the lever 55 to rock downwards, and the latter pulls down the bar 56 and the lever 23a with its roller 28a. At the same time the forked end of the lever 51 is rocked upwards about 51a by the link 58, so that the bar 59 is raised, and consequently also the lever 22a. This increases the distance between the axes of the smoothing rollers 28, 28a and the pressure on the work between the smoothing rollers is reduced. In the meantime the feeder I2 will have commenced its return movement, and owing to the connection of the lever guide 240, with the rocker lever 9 by the link 48 the whole lever arrangement takes part in the feeder movement. The feeder 52 now begins to lift, and at the same time the action of cam 49 ceases, so that the levers 22a, 23a are again able to bear on the work with their full spring pressure. The feeder [2 then lifts and begins to feed the work, and the levers 22a, 23a move with the feeder and thereby assist in the feed operation.

Depression of the bracket 54 by the lever 50 occurs each time a feed movement of the work is completed. It causes the bar 23a to be pulled down by the lever 55 and the bar 2211 to be lifted by the lever 57, so that the edge rubbing rollers 28, 28a are moved apart. While they are held in this position the cloth feed members are retracted, and their movement causes the edge rubbing members to swing back horizontally about the axis of the pivot 41. Then the cam 49 allows the spring connecting the bars 22a, 23a to pull them towards each other, so that they again engage the cloth.

Reverting to Figs. 1 to 5 it will be seen that the machine therein shown has a casing enclosing the principal parts of the driving mechanism. This casing has a compartment 32, in which is the shaft 2. Lubricating oil is poured into this compartment through a hole closed by a stopper 3|. The oil fills a sump 33 at the bottom of this compartment and overflows, passing through a hole 35 into a compartment in the foot of the machine, so that an oil bath 35 is formed therein. From the bath 35 flexible elastic oil wicks 36, ST, 38, 39 carry oil to the shafts 6 and I8, and from the sump 33 a wick 40 supplies oil to the wheels l6 and ll. Wicks 4!, 42 and 43 supply oil to the shafts 2 and 3. The bottom of the wheel' 5 is in the oil bath 85. Oil can be drained out of the foot of the machine by opening a screw stopper 46 (Fig. 4).

What I claim is:-

1. A sewing machine having in combination work feeding mechanism, stitch forming mechanism and edge rubbing mechanism, said rubbing mechanism comprising two roller carriers, rollers rotatable on said carriers and adapted to engage the work between them, and means for reciprocating said roller carriers in opposite directions transversely of the line of feed.

2. A sewing machine having in combination work feeding mechanism, stitch forming mechanism and edge rubbing mechanism, said rubbing mechanism comprising two roller carriers, rollers rotatable on said carriers and adapted to engage the work between them, said rollers having circumferential serrations, and means for reciproeating said roller carriers in opposite directions transversely of the line of feed.

3. A sewing machine having in combination work feeding mechanism, stitch forming mechanism and edge rubbing mechanism, said rubbing mechanism comprising two roller carriers, rollers rotatable on said carriers and adapted to engage the work between them, jaws carried by said roller carriers, adapted to engage the work between said rollers and said feed mechanism, and means for reciprocating said roller carriers in opposite directions transversely of the line of feed.

4. A sewing machine having in combination work feeding mechanism, stitch forming mechanism and edge rubbing mechanism, said rubbing mechanism comprising two roller carriers, rollers rotatable on said carriers and adapted to engage the work between them, adjustable jaws carried by said roller carriers, adapted to engage the work between said rollers and said feed mechanism, and means for reciprocating said roller carriers in opposite directions transversely of the line of feed.

5. A sewing machine having in combination work feeding mechanism, stitch forming mechanism and edge rubbing mechanism, said rubbing mechanism comprising two roller carriers, rollers rotatable on said carriers and adapted to engage the work between them, means for reciprocating said roller carriers parallel with the line of feed, and means for reciprocating said roller carriers in opposite directions transversely of the line of feed.

6. A sewing machine having in combination work feeding mechanism, stitch forming mechanism and edge rubbing mechanism, said rubbing mechanism comprising two roller carriers, rollers rotatable on said carriers and adapted to engage the work between them, means for reciprocating said roller carriers parallel with the line of feed,

means whereby said roller carriers are moved apart for disengaging said rollers from the work on completion of each movement in the direction of feed and are caused to move towards each other on completion of each movement opposed to the direction of feed, and means for reciprocating said roller carriers in opposite directions transversely of the line of feed.

'7. A sewing machine having in combination work feeding mechanism, stitch forming mechanism, edge rubbing mechanism including two rollers rotatable about their axes and means for reciprocating said rollers in opposite directions, in contact with the work, transversely of the line of feed, and a casing enclosing the driving members of said stitch forming and edge rubbing mechanism and adapted to hold oil so that oil can be fed by wicks to said driving members.

ALFONS STROBEL. 

